Production of acrylic acid and ethanol from carbonaceous materials

ABSTRACT

A process for producing acrylic acid from carbonaceous materials such as biomass. The carbonaceous material, such as biomass, is gasified to produce synthesis gas. The synthesis gas then is subjected to a plurality of reactions to produce acrylic acid.

This application is a CIP application that claims priority based onapplication Ser. No. 13/894,567, filed May 15, 2013, now U.S. Pat. No.9,150,488, which claims priority of provisional Application Ser. No.61/663,112, filed Jun. 22, 2012, the contents of which are incorporatedby reference in their entirety.

This invention relates to the production of acrylic acid fromcarbonaceous materials, such as biomass, municipal solid wastes, andindustrial waste materials. More particularly, this invention relates togasifying carbonaceous materials to produce synthesis gas, and toproducing acrylic acid and ethanol from such synthesis gas.

Synthesis gas, or syngas, includes carbon monoxide (CO) and hydrogen(H₂), with small amounts of carbon dioxide and residual hydrocarbons,and has a variety of uses. Synthesis gas may be used as a fuel gas ininternal combustion engines, in gas turbines, as well as in gas firedsteam boiler plants, or may be used to produce other desired materials,such as methanol and ethanol.

Synthesis gas may be produced by gasifying carbonaceous materials, suchas residual biomass materials, such as forest residues agriculturalresidues, spent structural wood materials, and urban biomass, such asmunicipal solid waste, and industrial solid waste. The gasification ofsuch materials provides a crude synthesis gas. The crude synthesis gasmay be purified to remove impurities such as ammonia (NH₃), sulfurcompounds (such as hydrogen sulfide (H₂S) and carbonyl sulfide (COS),chlorine compounds (such as HCl), volatile metals, tars, fines (in theform of sub-micron particles containing metals and metal salts), andchar (solid particulates typically above 0.001 mm and containing carbon,metals, and metal salts). The purified syngas then may be used as a fuelor be used to produce other materials.

In accordance with an aspect of the present invention, there is provideda process for producing acrylic acid from a carbonaceous material. Theprocess comprises gasifying the carbonaceous material to provide a crudesynthesis gas. The crude synthesis gas then is purified to provide apurified synthesis gas. At least a portion of the carbon monoxide fromthe purified synthesis gas is reacted with hydrogen from the purifiedsynthesis gas to produce methanol. The methanol then is reacted underconditions to provide a product comprising at least one olefin. The atleast one olefin comprises propylene. The propylene is subjected to oneor more reaction steps to produce acrylic acid.

In a non-limiting embodiment, the at least one olefin further comprisesethylene and the ethylene is reacted to produce ethanol.

In another non-limiting embodiment, the propylene is oxidized to produceacrylic acid.

In yet another non-limiting embodiment, the ethylene is oxidizedpartially to produce ethanol and the propylene is oxidized to produceacrylic acid.

Carbonaceous materials which may be gasified in accordance with thepresent invention include, but are not limited to, biomass-richmaterials.

Biomass-rich materials which may be gasified in accordance with thepresent invention include, but are not limited to, homogenousbiomass-rich materials, non-homogeneous biomass-rich materials,heterogeneous biomass-rich materials, and urban biomass.

In general, homogeneous biomass-rich materials are biomass-richmaterials which come from a single source. Such materials include, butare not limited to, materials from coniferous trees or deciduous treesof a single species, agricultural materials from a plant of a singlespecies, such as hay, corn, or wheat, for example, primary sludge fromwood pulp, and wood chips.

Non-homogeneous biomass-rich materials in general are materials whichare obtained from plants of more than one species. Such materialsinclude, but are not limited to, forest residues from mixed species, andtree residues from mixed species obtained from debarking operations orsawmill operations.

Heterogeneous biomass-rich materials in general are materials thatinclude biomass and non-biomass materials such as plastics, metals,and/or contaminants such as sulfur, halogens, or non-biomass nitrogencontained in compounds such as inorganic salts or organic compounds.Examples of such heterogeneous biomass-rich materials include, but arenot limited to, urban biomass such as municipal solid waste, such asrefuse derived fuel, solid recovered fuel, sewage sludge, usedelectrical transmission poles and railroad ties, which may be treatedwith creosote, pentachlorophenol, or copper chromium arsenate, and woodfrom construction and demolition operations which may contain one of theabove chemicals as well as paints and resins.

In a non-limiting embodiment, prior to the gasification of the biomass,the biomass is admixed with at least one additive material, whichneutralizes impurities such as chlorine, fluorine, and sulfur, which maybe present in the biomass. In a non-limiting embodiment, the at leastone additive is at least one adsorbent material. Such adsorbentmaterials include, but are not limited to, calcium oxide, or mixtures ofcalcium oxide, calcined limestone, ash materials, olivine (a silicate ofiron and magnesium), and mixtures of calcium and magnesium oxides.

In another non-limiting embodiment, the at least one additive materialis added to the biomass in an amount of from about 1.25 to about 3.0times the stoichiometric quantity required for full neutralization ofchlorine and other halogens, as well as sulfur present in the biomass.The term “neutralization,” as used herein, includes the formation ofstable salts such as CaCl₂, CaF₂, CaS, and the corresponding salts ofmagnesium and iron.

Gasification of the carbonaceous material, such as biomass, may beeffected by means known to those skilled in the art. For example, in anon-limiting embodiment, the biomass may be gasified in a gasifier whichincludes a fluidized bed section and a reforming, or freeboard, section.Examples of such gasifiers are disclosed in published PCT ApplicationNos. WO2009/132449 and WO2010/069068.

In a non-limiting embodiment, the carbonaceous material, such asbiomass, in a first step, is contacted in the fluidized bed section ofthe gasifier under conditions which effect a partial oxidation of thebiomass. As a result of the partial oxidation, the biomass decomposesthermally, and there are produced a solid carbonaceous residue, gases,such as CO₂, steam, and some carbon monoxide and hydrogen, and vapors ofintermediate species such as low molecular weight alkyl and aromatichydrocarbons, and phenolics such as phenol, catechols, and methoxylated,alkylated, and alkoxylated phenols.

In a non-limiting embodiment, the biomass, in a first step, is heated inthe fluidized bed section of a gasifier to a temperature of at least500° C. and no greater than 1,000° C. In another non-limitingembodiment, the biomass, in the first step, is heated to a temperatureof at least 550° C. and no greater than 900° C. In another non-limitingembodiment, the biomass, in the first step, is heated to a temperatureof at least 550° C. and no greater than 800° C. In a furthernon-limiting embodiment, the biomass, in the first step, is heated to atemperature of at least 600° C. and no greater than 700° C. In yetanother non-limiting embodiment, the biomass, in the first step, isheated to a temperature of at least 600° C. and no greater than 660° C.

In a non-limiting embodiment, the oxidizing gas, in the first step,further comprises nitrogen in an amount which does not exceed 80 vol. %of the oxidizing gas. In one non-limiting embodiment, the oxidizing gasincludes oxygen-enriched air and steam, in which oxygen is present in anamount of up to about 40 vol. % of the oxidizing gas, and nitrogen ispresent in an amount that does not exceed 80 vol. % of the oxidizinggas.

In another non-limiting embodiment, the biomass, in the first step, iscontacted with oxygen and steam in the absence of nitrogen. In anon-limiting embodiment, oxygen is present in such nitrogen-free gas inan amount about 5 vol. % to about 100 vol. %. In another non-limitingembodiment, oxygen is present in an amount of from about 5 vol. % toabout 40 vol. %. In yet another non-limiting embodiment, oxygen ispresent in such nitrogen-free gas in an amount of from about 30 vol. %to about 40 vol. %.

In another non-limiting embodiment, the oxidizing gas, in the firststep, includes carbon dioxide. In a further non-limiting embodiment,carbon dioxide is present in the oxidizing gas in an amount of fromabout 5 vol. % to about 100 vol. %. In a further non-limitingembodiment, carbon dioxide is present in the oxidizing gas in an amountof from about 5 vol. % to about 40 vol. %. In yet another non-limitingembodiment, carbon dioxide is present in the oxidizing gas in an amountof from about 10 vol. % to about 20 vol. %.

In a further non-limiting embodiment, oxygen is present in the oxidizinggas in an amount of from about 30 vol. % to about 40 vol. %, carbondioxide is present in the oxidizing gas in an amount of from about 10vol. % to about 20 vol. %, and the remainder of the oxidizing gasessentially is steam. Trace amounts of argon may be present.

In another non-limiting embodiment, the biomass, in the first step, iscontacted with oxygen at a weight ratio of oxygen to biomass thatbiomass is from about 0.1 to about 0.5 times the stoichiometric weightratio needed for complete combustion, i.e., total oxidation of thebiomass.

In a further non-limiting embodiment, the biomass, in the first step, iscontacted with oxygen at a weight ratio of oxygen to biomass of fromabout 0.2 to about 0.35 weight of the stoichiometric weight ratio neededfor complete combustion of the biomass. In yet another non-limitingembodiment, the biomass is contacted with oxygen at a weight ratio ofoxygen to biomass of from about 0.25 to about 0.30 of the stoichiometricweight ratio needed for complete combustion of the biomass.

In another non-limiting embodiment, in the first step, the biomass iscontacted with oxygen and steam in a bed of particulate material,whereby the passage of oxygen and steam through such bed provides afluidized bed of the particulate material. Such particulate materialsinclude, but are not limited to, alumina, olivine, silica, anthracite,desulfurized petroleum coke, and in general, any stable refractorymaterial. In a non-limiting embodiment, the particulate material isselected from the group consisting alumina, olivine and silica. Inanother non-limiting embodiment, the particles have a diameter of fromabout 50 microns to about 600 microns.

In another non-limiting embodiment, the biomass is contacted, in thefirst step, with oxygen and steam for a period of time that does notexceed 10 seconds. In a further non-limiting embodiment, the biomass iscontacted, in the first step, with oxygen and steam for a period of timethat does not exceed 3 seconds. In yet another non-limiting embodiment,the biomass is contacted, in the first step, with oxygen and steam for aperiod of time that does not exceed one second.

As the biomass is contacted with oxygen and steam in the first step, thebiomass is oxidized partially, and is decomposed thermally, therebyproducing a solid carbonaceous residue, gases such as CO₂, steam, andsome carbon monoxide (CO) and hydrogen (H₂), and vapors of intermediatespecies such as low molecular weight alkyl and aromatic hydrocarbons,and phenolics as hereinabove described.

When the biomass is contacted with oxygen and steam, in the first step,in the presence of a fluidized bed, the solid carbonaceous residueproduced in the first step remains in the fluidized bed and provides thebulk of the exothermal heat of oxidation, thereby maintaining thefluidized bed at the temperatures hereinabove described. The oxygen usedin the first step essentially is consumed in such step, while a portionof the carbonaceous residue formed during the first step is consumed aswell, and another portion of the carbonaceous residue is entrained aschar. The char particles also may contain inorganic materials initiallypresent in the biomass feedstock.

Some cracking of intermediates, i.e., low molecular weight hydrocarbons,phenolics, and aromatics, may occur during the first step; however,higher temperatures are required to convert the residual carbon in theentrained char particles, and additionally to crack and reform theintermediate vapors containing the low molecular weight alkyl andaromatic hydrocarbons, and phenolics. Thus, in a second step, at least aportion of the partially oxidized biomass produced in the first step istreated in the freeboard section of the gasifier with an oxidizing gascomprising oxygen and steam to heat the biomass to a temperature of atleast 800° C. to produce synthesis gas.

In a non-limiting embodiment, the partially oxidized and thermallydecomposed biomass, in the second step, is heated to a temperature offrom about 800° C. to about 1,200° C. In another non-limitingembodiment, the oxidized biomass, in the second step, is heated to atemperature of from about 900° C. to about 1,100° C. In yet anothernon-limiting embodiment, the oxidized biomass, in the second step, isheated to a temperature of from about 925° C. to about 1,000° C.

In a non-limiting embodiment, the oxidizing gas, in the second step,further comprises nitrogen in an amount which does not exceed 60 vol. %of the oxidizing gas. In one non-limiting embodiment, the oxidizing gasincludes oxygen-enriched air and steam, in which oxygen is present in anamount of up to about 40 vol. % of the oxidizing gas, and nitrogen ispresent in an amount that does not exceed 60 vol. % of the oxidizinggas.

In another non-limiting embodiment, the partially oxidized biomass, inthe second step, is contacted with oxygen and steam in the absence ofnitrogen. In a non-limiting embodiment, oxygen is present in suchnitrogen-free gas in an amount which does not exceed 40 vol. %. In yetanother non-limiting embodiment, oxygen is present in such nitrogen-freegas in an amount of from about 30 vol. % to about 40 vol. %.

In another non-limiting embodiment, the oxidizing gas, in the secondstep, further comprises carbon dioxide. In a further non-limitingembodiment, carbon dioxide is present in the oxidizing gas in an amountthat does not exceed 20 vol. %. In yet another non-limiting embodiment,carbon dioxide is present in the oxidizing gas in an amount of fromabout 10 vol. % to about 20 vol. %.

In a further non-limiting embodiment, oxygen is present in suchoxidizing gas in an amount of from about 30 vol. % to about 40 vol. %,carbon dioxide is present in the oxidizing gas in an amount of fromabout 10 vol. % to about 20 vol. %, and the remainder of the oxidizinggas essentially is steam. Trace amounts of argon may be present.

In a non-limiting embodiment, the oxidized biomass, in the second step,is treated with the oxygen and steam for a period of time of from about0.5 seconds to about 10 seconds. In another non-limiting embodiment, theoxidized biomass, in the second step, is treated with the oxygen andsteam for a period of time of from about 4 seconds to about 8 seconds.

Alternatively, in a further non-limiting embodiment, the oxidizedbiomass, in the second step, is treated with oxygen and steam in a firststage to a temperature of at least 800° C., followed by furthertreatment with oxygen and steam in a second stage. The oxidized biomassis heated to a temperature in the second stage which is higher than thatof the first stage. In a non-limiting embodiment, the oxidized biomassis heated in the first stage to a temperature of at least 800° C. anddoes not exceed 850° C.

In a non-limiting embodiment, the partially oxidized and thermallydecomposed biomass, in the second step, is heated to a temperature offrom about 800° C. to about 1500° C.

In another non-limiting embodiment, the oxidized biomass, in the secondstep, is heated to a temperature of from about 900° C. to about 1,100°C.

In a non-limiting embodiment, the partially oxidized and thermallydecomposed biomass, in the second step, is heated to a temperature offrom about 800° C. to about 1,200° C. In another non-limitingembodiment, the oxidized biomass, in the second step, is heated to atemperature of from about 900° C. to about 1,100° C. In yet anothernon-limiting embodiment, the oxidized biomass, in the second step, isheated to a temperature of from about 925° C. to about 1,000° C.

In another non-limiting embodiment, the oxidized biomass is heated inthe second stage to a temperature of at least 900° C. In a furthernon-limiting embodiment, the oxidized biomass is heated in the secondstage to a temperature of from about 900° C. to about 1,000° C. In yetanother non-limiting embodiment, the oxidized biomass is heated in thesecond stage to a temperature of from about 925° C. to about 975° C.

In yet another non-limiting embodiment, the oxidized biomass is heatedin the first stage to a temperature of from 800° C. to 850° C., and isheated in the second stage to a temperature of from 925° C. to 975° C.

When the oxidized biomass is contacted with oxygen and steam in thesecond step, whereby the oxidized biomass is heated to a temperature ofat least 800° C., carbon in the char is converted fully by the steam togenerate hydrogen and carbon monoxide, and steam reforming of theintermediates yields more hydrogen and carbon monoxide. In general, theinorganic materials which are present in the char in general are exposedto temperatures higher than their melting points. Such inorganicmaterials will melt and stay melted in the char particles. Deposition ofchar particles and/or inorganic materials on the walls of thegasification vessel is minimal because the particles are entrained underplug flow conditions.

In another non limiting embodiment the oxidized biomass is contactedwith oxygen and steam in the second step, whereby the oxidized biomassis heated to a temperature of at least 1300° C., carbon in the char isconverted fully by the steam to generate hydrogen and carbon monoxide,and steam reforming of the intermediates yields more hydrogen and carbonmonoxide. In general, the inorganic materials which are present in thechar in general are exposed to temperatures higher than their meltingpoints. Such inorganic materials will melt and stay melted in the charparticles.

In another non limiting embodiment the oxidized biomass is contactedwith oxygen and steam in the second step, whereby the oxidized biomassis heated to a temperature of at least 1500° C., carbon in the char isconverted fully by the steam to generate hydrogen and carbon monoxide,and steam reforming of the intermediates yields more hydrogen and carbonmonoxide. In general, the inorganic materials which are present in thechar in general are exposed to temperatures higher than their meltingpoints. Such inorganic materials will melt and stay melted in the charparticles.

In general, the gasifier is operated at a pressure that does not exceed10 atm. The fluidized bed section includes particles of a fluidizablematerial, such as alumina or olivine, having a particle size of fromabout 50 microns to about 600 microns. Oxygen and steam are introducedinto the fluidized bed section of the gasifier to provide a gas velocityof from about 0.7 m/sec. to about 1.5 m/sec., thereby providing abubbling fluidized bed of the particulate material.

The gas and vapors produced in the fluidized bed section pass throughthe disengaging zone into the freeboard section, in which the gas andvapors are contacted with oxygen and steam to reach a temperature offrom about 925° C. to about 1,000° C. The oxygen and steam areintroduced into the freeboard section of the gasifier in such an amountthat the velocity of the gaseous phase is maintained from about 0.3m/sec. to about 0.7 m/sec. In general, gas residence times in thefreeboard section of the gasifier are from about 4 seconds to about 8seconds.

In the freeboard section, the phenolics are converted into simplearomatics, and tar cracking and tar reforming are effected. Carbon inthe char essentially is converted fully by the steam and CO₂ to generateH₂ and CO, and steam reforming of the vapors of the intermediatehydrocarbons also generates H₂ and CO. Inorganic materials present inthe char will melt. Deposition of inorganic materials on the walls ofthe gasifier, however, is minimal due to particle entrainment in theexisting plug flow regime.

As noted hereinabove, in one alternative non-limiting embodiment, theheating of the partially oxidized biomass to produce synthesis gas maybe effected in a combination of a first stage, and a second stage,wherein the partially oxidized biomass is heated to a temperature in thesecond stage which is greater than that of the first stage.

In one non-limiting embodiment, the first stage is conducted in thefreeboard section of the gasifier, and the second stage is conducted inone or more tubular flow reactors. In a non-limiting embodiment, the oneor more tubular flow reactor(s) is (are) in the form of refractorizedand insulated carbon steel pipes. In another non-limiting embodiment,the heating in the second stage is conducted in two tubular flowreactors which are connected to each other so as to form a U-shapedconfiguration.

In a non-limiting embodiment, the oxidized biomass is contacted withoxygen and steam in the freeboard section of the gasifier at atemperature of from about 800° C. to about 850° C. The oxygen and steamare introduced into the freeboard section of the gasifier in suchamounts that maintain a gaseous velocity of from about 0.3 m/sec. toabout 0.7 m/sec., and the reaction time is from about 4 seconds to about8 seconds, as hereinabove described, to begin the conversion of theoxidized biomass to a crude synthesis gas. The gas produced in thefreeboard section also has char particles entrained therein.

The gas and entrained particles then are passed from the freeboardsection of the gasifier to one or more tubular flow reactors. In anon-limiting embodiment, additional oxygen and steam are added to thetubular flow reactor(s). In the tubular flow reactor(s), the gas isheated to a temperature of from about 925° C. to about 975° C., and ingeneral, the reaction time in the tubular flow reactor(s) is from about1 second to about 2 seconds, which is sufficient to complete theconversion of the oxidized biomass to a crude synthesis gas.

In another non-limiting embodiment, additional oxygen and steam areadded to the reactor(s). In the reactor(s), the gas is heated to atemperature of from about 925° C. to about 1300° C., and in general, thereaction time in the reactor(s) is from about 1 second to about 3seconds, which is sufficient to complete the conversion of the oxidizedbiomass to a crude synthesis gas. The reactors include a single reactorvessel or tubular flow reactors.

The gas and entrained particles then are passed from the freeboardsection of the gasifier to one or more reactors. In a non-limitingembodiment, additional oxygen and steam are added to the reactor(s). Inthe reactor(s), the gas is heated to a temperature of from about 925° C.to about 1500° C., and in general, the reaction time in the reactor(s)is from about 1 second to about 3 seconds, which is sufficient tocomplete the conversion of the oxidized biomass to a crude synthesisgas. The reactors include a single reactor vessel or tubular flowreactors.

A crude synthesis gas product thus is produced by gasifying biomass inthe fluidized bed and freeboard sections of the gasifier, and optionallyin one or more tubular flow reactors, under the conditions hereinabovedescribed. Such crude synthesis gas then is conditioned to provide aclean synthesis gas.

In a non-limiting embodiment, crude synthesis gas is cooled, and thenpassed through one or more cyclones to remove larger particles, such aschar particles. In a non-limiting embodiment, the particles removed bythe one or more cyclones have a size over 10 microns.

After the particles have been removed from the crude synthesis gas, thecrude synthesis gas may be scrubbed in a scrubbing system to removefines and impurities such as HCl, H₂S, and ammonia, as well as sodiumsalts and tar, to provide a purified synthesis gas. Examples of thepreparation of a crude synthesis gas, and of the purification of a crudesynthesis gas are described in published PCT Application Nos.WO2010/069068 and WO2009/132449, the contents of which are incorporatedby reference.

Once a purified synthesis gas is produced, at least a portion of thehydrogen and at least a portion of the carbon monoxide in the synthesisgas are reacted to produce methanol. In a non-limiting embodiment, aportion of the hydrogen and a portion of the carbon monoxide in thesynthesis gas are reacted in the presence of a suitable methanolsynthesis catalyst, such as a copper oxide based catalyst, such as aCu/ZnO/Al₂O₃ catalyst or a Cu/ZnO catalyst in oil, to produce methanol.In a non-limiting embodiment, the catalyst may be on stream for at least5,000 hours before regeneration. In another non-limiting embodiment, thehydrogen and carbon monoxide are reacted to produce methanol at a ratioof hydrogen to carbon monoxide of from about 0.6:1 to about 3:1.

In general, the hydrogen and carbon monoxide are reacted to producemethanol according to the following equation:CO+2H₂→CH₃OH

In a non-limiting embodiment, the methanol then is subjected todehydration to produce at least one ether, such as dimethyl ether, orDME, according to the following equation:2CH₃OH→CH₃COCH₃+H₂O

The methanol may be subjected to dehydration to produce dimethyl etherin the presence of a dehydration catalyst. In a non-limiting embodiment,the dehydration catalyst is gamma-alumina.

In a non-limiting embodiment, the hydrogen and carbon monoxide of thesynthesis gas are reacted at a pressure of from about 250 to about 2,000psi. In another non-limiting embodiment, the hydrogen and carbonmonoxide are reacted at a pressure of from about 300 to about 1,500 psi.In another non-limiting embodiment, the hydrogen and carbon monoxide arereacted at a temperature of from about 100° C. to about 300° C. Inanother non-limiting embodiment, the hydrogen and carbon monoxide arereacted at a molar ratio of from about 1:1 to about 3:1.

In a further non-limiting embodiment, the hydrogen and carbon monoxideare reacted in the presence of an “integrated” methanol synthesis anddehydration catalyst which may be suspended in an inert oil, such aswhite mineral oil or Drakeol, into which the hydrogen and carbonmonoxide are bubbled. In such an embodiment, the hydrogen and carbonmonoxide are reacted in the presence of the “integrated” catalyst toproduce methanol. The methanol then is reacted immediately in thepresence of the “integrated” catalyst to produce dimethyl ether andwater.

In a non-limiting embodiment the hydrogen and the carbon monoxide arereacted in the presence of a methanol catalyst in a first reactor toproduce methanol, and then the methanol is reacted in the presence of adehydration catalyst in a second reactor to produce at least one ether,such as DME.

The DME then is purified to remove the residual hydrogen, carbonmonoxide and water. The purified DME then is passed to a reactor suchas, for example, in a non-limiting embodiment, a packed bed reactor toproduce a product that comprises at least one olefin, wherein the atleast one olefin includes propylene. The synthesis of the at least oneolefin, including propylene, in a non-limiting embodiment, is carriedout in a fixed bed reactor using an acid catalyst at 200 to 550° C. and1 to 30 atm. Catalysts which may be used for this reaction include, butare not limited to, one or more zeolites, gamma alumina, or other acidicmaterials.

The DME is reacted to produce olefins, methane, and aromatics. Olefinswhich may be produced by reacting DME as hereinabove described includepropylene and ethylene. Depending upon the catalyst used for the olefinsynthesis, the propylene selectivity may be between 70% and 95%.

In a non-limiting embodiment, the propylene is oxidized to acrolein.This reaction, in a non-limiting embodiment, is carried out in a fixedbed reactor in the temperature range 250 to 450° C. Catalysts used forthis reaction may be, but are not limited to, multicomponent metal oxidebased catalysts. In a non-limiting embodiment, the catalyst is an Mo—Bibased catalyst. Examples of such catalysts are described in Nojiri, etal., Science and Engineering, Vol. 37, pgs. 145-170 (1995), U.S. Pat.No. 7,731,919, and published U.S. Patent Application No. 2007/0213567.

The acrolein then is reacted in another oxidation reactor to produceacrylic acid. After the acrolein is reacted in the oxidation reactor toproduce acrylic acid, any unreacted acrolein is separated for theacrylic acid and is recycled to the acrolein oxidation reactor, and theresulting acrylic acid product is recovered.

Alternatively, in a non-limiting embodiment, the propylene is reacted ina partial oxidation reactor to produce acrylic acid in the presence of acobalt and nickel molybdate based catalyst.

BRIEF DESCRIPTION OF THE DRAWING

The invention now will be described with respect to the drawing, wherein

The drawing is a schematic of an embodiment of a process for producingacrylic acid in accordance with a non-limiting embodiment of the presentinvention.

Referring now to the drawing, a biomass feed in line 11 is fed togasification unit 12 to provide a crude synthesis gas. The crudesynthesis gas is withdrawn from gasification unit through line 13 and issubjected to thermal reforming in reformer 14 to provide additionalsynthesis gas. The resulting crude synthesis gas is withdrawn fromreformer 14 through line 15 and is subjected to a series of purificationsteps, indicated schematically as 16. The purified synthesis gas then ispassed to line 17 and into three phase methanol reactor 18, whichcontains a catalyst suspended in an inert oil.

In the methanol reactor 18 the carbon monoxide and hydrogen of thepurified synthesis gas are reacted to produce methanol. The methanolcontaining product is withdrawn from reactor 18 through line 19 and issubjected to a purification process, indicated schematically as 20. Thecarbon monoxide and the hydrogen are separated from the methanol and arerecycled through line 21 to line 17. Purified methanol is passed throughline 22 to packed bed reactor 23 wherein the methanol is reacted to forman ether product, mainly dimethyl ether. The dimethyl ether containingproduct is withdrawn from the reactor 23 through line 24 and issubjected to a purification process, indicated schematically as 25.Unreacted methanol is separated from the DME and water and is recycledthrough line 26 to line 22. Water generated from the DME synthesis couldbe used for heat generation.

Purified DME is passed though line 27 to a packed bed reactor 28 whereinthe DME is reacted to form an olefin product including ethylene andpropylene. The olefin product is withdrawn form the reactor 28 throughline 29 and is subjected to a separation process, indicatedschematically as 30.

Unreacted DME is separated from the ethylene and propylene and recycledthrough line 31 to line 27.

Propylene is withdrawn form separation process 30 through line 32 and ispassed to partial oxidation reactor 33 where propylene is reacted toproduce acrolein. The acrolein and the unreacted propylene are withdrawnfrom the partial oxidation reactor 33 through line 34 and then aresubjected to a separation process, indicated schematically as 35.Unreacted propylene is withdrawn form the separation process 35 throughline 36 and is recycled to line 32. Acrolein is withdrawn fromseparation process 35 through line 37 and is passed to partial oxidationreactor 38 where the acrolein is reacted to produce acrylic acid.Acrylic acid and unreacted acrolein are withdrawn from the partialoxidation reactor 38 through line 39 and then are subjected to aseparation process indicated schematically as 40. Unreacted acrolein iswithdrawn from separation process 40 through line 41 and is recycled toline 37. Acrylic acid is recovered from separation process 40 throughline 42.

Ethylene is withdrawn from the separation process 30 through line 43 andpassed to partial oxidation reactor 44, where ethylene is reacted withoxygen to produce ethanol. Ethanol and unreacted ethylene are withdrawnfrom the partial oxidation reactor 44 through line 45 and are subjectedto a separation process, indicated schematically at 46. Unreactedethylene is withdrawn from separation process 46 through line 48 andrecycled to line 43. Ethanol is recovered form separation process 46through line 47.

The disclosures of all patents and publications, including publishedpatent applications, are incorporated herein by reference as if eachpatent and publication were incorporated individually by reference.

It is to be understood, however, that the scope of the present inventionis not to be limited to the specific embodiments described above. Theinvention may be practiced other than as particularly described andstill be within the scope of the accompanying claims.

What is claimed is:
 1. A process for producing acrylic acid and ethanolfrom biomass comprising: (a) contacting said biomass with an oxidizinggas comprising oxygen and steam, thereby oxidizing said biomass; (b)treating, in a first stage, at least a portion of said oxidized biomassproduced in step (a) with an oxidizing gas comprising oxygen and steamto heat and reform said oxidized biomass, and provide an oxidizedbiomass containing residual carbon in char particles entrained in saidoxidized biomass, and low molecular weight alkyl and aromatichydrocarbons and phenolics in said oxidized biomass; (c) treating, in asecond stage, at least a portion of said oxidized biomass containingresidual carbon in char particles entrained in said oxidized biomass,and low molecular weight alkyl and aromatic hydrocarbons and phenolicsin said oxidized biomass, produced in step (b) with an oxidizing gascomprising oxygen and steam to heat said oxidized biomass to atemperature from about 800° C. to about 1500° C., thereby producing acrude synthesis gas; (d) purifying the crude synthesis gas to provide apurified synthesis gas; (e) reacting at least a portion of the carbonmonoxide from said purified synthesis gas with hydrogen from saidpurified synthesis gas to provide a product stream containing dimethylether; (f) separating said dimethyl ether from said product stream ofstep (e) and reacting said dimethyl ether to provide a productcomprising propylene and ethylene; (g) reacting said ethylene to produceethanol; and (h) subjecting said propylene to one or more reaction stepsto produce acrylic acid.
 2. The process of claim 1 wherein step (c) isconducted in one or more tubular flow reactors.
 3. The process of claim2 wherein, in step (c), said oxidized biomass is heated to a temperatureof from about 925° C. to about 1,300° C.
 4. The process of claim 1wherein said dimethyl ether is reacted in step (f) in the presence of anacid catalyst.
 5. The process of claim 4 wherein said acid catalyst is azeolite.
 6. The process of claim 1 wherein, in step (h), said propyleneis reacted in a partial oxidation reactor to produce acrylic acid in thepresence of a cobalt and nickel molybdate containing catalyst.
 7. Theprocess of claim 1 wherein, in step (h), said propylene is oxidized toproduce acrolein, and said acrolein is reacted in an oxidation reactorto produce acrylic acid.
 8. The process of claim 1 wherein, prior tostep (a), said biomass is admixed with at least one additive materialwhich neutralizes impurities which may be present in said biomass. 9.The process of claim 8 wherein said impurities are selected from thegroup consisting of chlorine, fluorine, and sulfur.
 10. The process ofclaim 8 wherein said at least one additive material is at least oneadsorbent material.
 11. The process of claim 8 wherein said at least oneadsorbent material is selected from the group consisting of calciumoxide, calcined limestone, ash materials, olivine, and mixtures ofcalcium and magnesium oxides.
 12. The process of claim 1 wherein steps(a) and (b) are conducted in a gasifier, said gasifier having afluidized bed section and a freeboard section, and wherein step (a) isconducted in said fluidized bed section and step (b) is conducted insaid freeboard section.
 13. The process of claim 2 wherein, in step (c),said oxidized biomass is heated to a temperature of from about 925° C.to about 1,500° C.
 14. The process of claim 1 wherein, in step (f), saidproduct further comprises methane and aromatics.
 15. The process ofclaim 1 wherein, in step (f), the propylene selectivity is between 70%and 95%.
 16. The process of claim 1 wherein step (e) is completed in asingle reactor, and wherein step (e) comprises: reacting at least aportion of the carbon monoxide from said purified synthesis gas withhydrogen from said purified synthesis gas in the presence of anintegrated methanol synthesis and dehydration catalyst, suspended in aninert oil, whereby said hydrogen and said carbon monoxide are reacted toproduce methanol, and said methanol is reacted to produce dimethyl etherand water.
 17. The process of claim 1 wherein, in step (c), said carbonin said char is converted to carbon monoxide.
 18. The process of claim1, and further comprising: prior to step (c), converting said phenolicsof step (b) into simple aromatics.
 19. The process of claim 12 whereinsaid oxygen and steam are introduced into the freeboard section of saidgasifier in amounts that provide a reaction time of from about 4 secondsto about 8 seconds.
 20. The process of claim 2 wherein said one or moretubular flow reactors include reflectorized and insulated carbon steelpipes.
 21. The process of claim 2 wherein, in step (c), the reactiontime is 1 to 3 seconds.
 22. A process for producing acrylic acid andethanol from biomass, comprising: (a) contacting said biomass with anoxidizing gas comprising oxygen and steam, thereby oxidizing saidbiomass; (b) treating, in a first stage, at least a portion of saidoxidized biomass produced in step (a) with an oxidizing gas comprisingoxygen and steam to heat and reform said oxidized biomass, and providean oxidized biomass containing residual carbon in char particlesentrained in said oxidized biomass, and low molecular weight alkyl andaromatic hydrocarbons and phenolics in said oxidized biomass; (c)treating, in a second stage, at least a portion of said oxidizedbiomass, containing residual carbon in char particles entrained in saidoxidized biomass, and low molecular weight alkyl and aromatichydrocarbons and phenolics in said oxidized biomass, produced in step(b) with an oxidizing gas comprising oxygen and steam to heat saidoxidized biomass to a temperature of at least 1,500° C., therebyproducing a crude synthesis gas; (d) purifying the crude synthesis gasto provide a purified synthesis gas; (e) reacting at least a portion ofthe carbon monoxide from said purified synthesis gas with hydrogen fromsaid purified synthesis gas to provide a product stream containingdimethyl ether; (f) separating said dimethyl ether from said productstream of step (e) and reacting said dimethyl ether to provide a productcomprising propylene and ethylene; (g) reacting said ethylene to produceethanol; and (h) subjecting said propylene to one or more reaction stepsto produce acrylic acid.